A prefabricated concrete slab is known from Austrian patent 246 962, Hasslinger, the reinforcement body of which comprises an upper and a lower reinforcement mat as well as several displacement bodies keeping these reinforcement mats at a distance. The displacement bodies are at a distance from one another such that the formation of concrete stiffening ribs of predetermined width and height is made possible in the prefabricated slab. The two reinforcement mats are bound together with the aid of connecting stirrups, which are arranged in the spaces provided for the stiffening ribs, and thus the displacement bodies are clamped between the two reinforcement mats.
The disadvantage in the construction of this reinforcement body is firstly the inadequate fixing of the position of the displacement bodies, which is carried out only by the stirrups mentioned above. The reinforcement body also does not have sufficient rigidity to prevent displacement of the reinforcement mats relative to one another, for example when transported. In addition, the connecting stirrups can absorb shear forces only to an inadequate extent, as a result of which there is no statically effective shear reinforcement of the stiffening ribs. Since also the displacement bodies rest on the lower reinforcement mat, the concrete covering is not adequate for the lower prefabricated slab.
A reinforced concrete building slab provided with at least one displacement body and with reinforced stiffening ribs is known from European specification 0 066 647, Heinz in which shear reinforcement of the stiffening ribs is formed by projections moulded from the lower reinforcement mat, it being possible to connect the tips of the projections with the upper reinforcement mat. This reinforcement has the disadvantage that the displacement body is inadequately fixed by the projections, and in addition the concrete covering is inadequate both for the lower reinforcement mat as well as the upper reinforcement mat. In addition, the reinforcement of the stiffening ribs cannot be selected independently of the shaping of the foundation reinforcement mat.